Japanese Unexamined Patent Application Publication No. 2013-24546 discloses the background art of the present technical field. This publication describes in paragraph 57 as “As mentioned above, data is collectively obtained from the centralized control devices 200a-200c connectable on a network, and the data interface server 500 can be responded to the communication equipment 300a and 300b. Therefore, for example, a serviceman only accesses the opportunity at the time of a pilot run of air-conditioning equipment, or a maintenance using the communication equipment 300a and 300b to the data interface server 500 in a building, It is possible to acquire the connection information and individual identification information of all the air-conditioning equipment [101a-101d and 102a-102d] in a building.”